What should be the acceptable range for positive readings according to the XRF analysis?

The acceptable range for positive readings according to XRF (X-ray fluorescence) analysis is at or greater than 1.0 mg/cm². This threshold is critical in lead safety assessments as it helps to determine if a surface has lead present at a concentration that poses a health risk, particularly for children and pregnant women.

Lead exposure can lead to serious health problems, and the XRF analysis is a non-destructive method that provides immediate results regarding lead content in paint, soil, and other materials. The value of 1.0 mg/cm² is significant in regulatory contexts, as it serves as a benchmark for identifying surfaces that require remediation or further testing. A reading at or above this level indicates that the lead concentration is potentially hazardous and requires appropriate safety measures.

Choices that suggest values below this threshold do not recognize the potential risks associated with lower lead concentrations. In contrast, stating an exact value does not consider the necessary variability in readings that might occur in practical application. The chosen threshold is crucial for ensuring safety and compliance with regulations concerning lead exposure.